This application claims the priority of Japanese Patent Application No.2003-307065 filed on Aug. 29, 2003, in the Japan Patent Office, the disclosure of which is incorporated by reference.
1. Field of the Invention
The present invention relates to a fluid mixing reaction enhancement method using a micro device, and a micro device, and in particular, relates to a fluid mixing reaction enhancement method using a micro device, and a micro device which can enhance a mixing reaction of fluids, which flow through the inside of a microchannel, without complicating microchannel structure and extending the microchannel.
2. Description of the Related Art
Since it is possible to perform micro fabrication in remarkably good accuracy and low cost owing to the development of processing technology in recent years, the development of apparatuses such as a mixing apparatus (micro mixer) and a chemistry reactor (micro reactor), which are in micro scale, and furthermore, a micro TAS (Total Analysis System: lab-on-a-chip) and a microchemistry plant have been attempted. These apparatuses, where minute spaces (hereinafter, “microchannels”) with opening widths in micron order which are connected to a plurality of fine fluid supply passes are provided, mix a plurality of fluids or perform reactions accompanied by mixing. It is common that the apparatuses such as the micro mixer, micro device, micro TAS, and microchemistry plant which are mentioned above have the above-mentioned basic structure of a microchannel, and hence, these apparatuses will be generically called micro devices in the present invention.
The micro device has unique advantages, which batch-scale operations do not have, such as the capability of operations, such as dissociation, analysis, and extraction, in a short time wit a small amount of samples by mixing or a mixing reaction of a plurality of fluids, the capability of quickly adapting for chemical production requiring job shop type production, the ease of numbering-up because of a small apparatus, and adaptability for dangerous reactions such as explosions.
Although a flow in a microchannel used as the fundamental of these micro devices is usually in a laminar flow state, its efficiency is low because a mixing reaction of fluids proceeds only by molecular diffusion in this case. Hence, it is necessary to terminate a mixing reaction for a short time by a certain method in most of mixing reactions except cases of requiring a maturation mixing reaction for a long time. Hence, it is very important practically to clarify a mixing reaction mechanism of fluids in a flow field in a microchannel, and to propose a method for enhancing a mixing reaction.
When reactants are supplied in mutually complete isolation in a flow field in a state that reactants are not mixed beforehand, that is, in a so-called initial state, a chemical reaction proceeds through molecular diffusion in a contact interface domain of the fluids containing respective reactants. Hence, in order to enhance the fluid mixing and chemical reaction in a general practical reactor, it becomes important not only how fast materials are transported, but also how a contact interface is deformed intricately. However, since the flow in the microchannel, which is a flow field is in a laminar flow state, there is no complexity in a contact interface, and hence, attentions have been paid on how to earn the molecule diffusion time of materials, For this reason, in regard to conventional micro devices, passive methods of attempting to increase the contact time of fluids, and the contact interface between fluids, have been adopted by complicating channel shapes, and extending the channels as a way of enhancing the mixing reaction of the fluids (for example, PCT International Publication WO 99/44736, and PCT International Publication WO 02/089965).